The present invention relates to a guide vane assembly for continuous-flow machines, particularly for Francis or Kaplan turbines and for pumps or pump turbines, with a plurality of guide vanes actuated by one link each on a common adjusting element, where safety elements are provided.
Adjusting elements are known on guide vane assemblies in which each or every second transmission mechanism has a safety element that limits the torque transmitted to the guide vanes during a closing operation. These safety elements are intended to prevent the full torque that the actuating device can apply to the common adjusting element being concentrated on the vanes that are prevented from closing when a solid body is trapped accidentally between two adjacent vanes, which could cause damage to the vanes or the adjusting element. The safety elements of this kind in use include shear pins or tension shear pins, which break before reaching the maximum permitted torque is exceeded and release the vane from the bracing at the same time. An adjusting device of this kind is shown in CH 444 787, for example. Other existing safety elements are articulated and bending links (e.g. JP 8074725 A), repositioning safety elements with spring elements (e.g. GB 0989828 A), and hydraulic systems (e.g. DE 1503299 A1).